1. For reviews of experimental work, see Canella, V., Mydosh, J.A.: AIP Conf. Proc.18, 651 (1974); Mydosh, J.A., in: Proc. Second Int. Symposium on Amorphous Magnetism, Troy, 1976 (R.A. Levy and R. Hasegawa, eds.) New York: Plenum Press 1977
2. Arrott, A.: J. Appl. Phys.36, 1093 (1965)
3. Canella, V., Mydosh, J.A.: Phys. Rev. B6, 4220 (1972)
4. Wenger, L.E., Keesom, P.H.: Phys. Rev. B13, 4053 (1976)
5. Zweers, H.A., Pelt, W., Nieuwenhuys, G.J., Mydosh, J.A., in: Proceedings of the Int. Conf. on Magnetism, Amsterdam 1976 (physica, in press)